How to change WebSocket payload?

[K]

Hello,

I am trying to change the WebSocket payload but getting the error:

"java.lang.ClassCastException: Cannot cast java.lang.String to [Bjava.lang.ClassCastException: Cannot cast java.lang.String to [B"

My script:

function onMessageFrame(msg, helper){
mss = msg.getReadablePayload();        
n = mss.indexOf("Red\":500");
if(n > 0) {
newmss = mss.replace("Red\":500", "Red\":100");
msg.setPayload( newmss );
}
}

Checked the ZAP code and it seems that setPayload method expect Object, but after replacing the text I am getting String.

public void setPayload(Object payload) {
this.payload = payload; }

https://github.com/zaproxy/zap-extensions/blob/main/addOns/websocket/src/main/java/org/zaproxy/zap/extension/websocket/WebSocketMessageDTO.java

What is the correct method how to change the WebSocket content?

[thc...@gmail.com]

Hi.

The scripts are passed in a WebSocketMessage not WebSocketMessageDTO.

You need to set a byte[] e.g.:

msg.setPayload( newmss.getBytes("UTF-8") );


Best regards.

[K]

Hello,

Thank you.

It solved my issue.